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Which chemicals do i need for my Hot Tub ?

Which chemicals do i need for my Hot Tub ?

What Chemicals Are Needed for a Hot Tub? Here Are the Essentials

As far as fun home improvement projects go, it's hard to beat a hot tub. From reducing stress to soothing pains, hot tubs come with many benefits.

If you've never had a hot tub before, though, you need to know how to keep it safe. This boils down to adding the right chemicals. Without them, your hot tub will become a breeding ground for bacteria and contaminants.

So, what chemicals are needed for a hot tub? Here's a quick list of what you'll need to keep your water balanced and enjoyable to soak in!

Hot Tub Sanitizer

Your sanitizer is the first line of defense against bacteria and algae. The two most common types of hot tub sanitizers are chlorine and bromine.


Chlorine is cheap, easy to manage, and very efficient at its job. As a result, it's one of the most popular hot tub maintenance supplies. The only downside to chlorine is its strong odor, often described as the "pool smell."

The reason for this smell is that chlorine kills bacteria through oxidation. This chemical reaction creates chloramines, which cause the odor. If you can smell it, your chlorine has likely been used up and you should add more.


If you don't like the chlorine smell, bromine is a solid alternative. This element is also gentler on your skin and lasts longer than chlorine. Plus, it has a lower pH, making it easier to keep your water balanced.

The main downsides of bromine are its price and the fact it works more slowly. It's also unstabilized, meaning it burns off quickly under the sun. This is why it's best used for indoor tubs or those that aren't in direct sunlight.

Alkalinity and pH Treatments

One confusing element of hot tub water care is the interplay of pH and alkalinity. The former measures how acidic the water is, and alkalinity acts as its buffer, preventing it from changing too much.

Ideally, the total alkalinity level in your tub should be 80-150 ppm. The pH should be between 7.4 and 7.6. High pH can cause dry and itchy skin, whereas low pH can corrode your hot tub.

Many products can raise or lower both alkalinity and pH at once. For best results, though, you should have some chemicals that only do one of those things. Here's a quick list.

Alkalinity Increaser

After testing your water, you'll always treat alkalinity levels before pH. That's because alkalinity has a larger influence over pH than the other way around. Adding baking soda is a good way to increase alkalinity.

pH Decreaser

Unfortunately, no chemical specifically reduces alkalinity levels. If these levels get too high, you'll need to use a pH decreaser to lower them. The best way to do that is to use sodium bisulfate.

pH Increaser

Once your pH gets too low, you'll use a pH increaser. Your best tool for this purpose is sodium carbonate, also known as soda ash. This chemical has a pH level of 11.4, making it perfect for turning water alkaline.

Hot Tub Shock

Every list of essential hot tub chemicals also includes hot tub shock. Think of it as a problem-solver. While your sanitizer works day-to-day, a shock treatment is a quick boost that helps it stay efficient.

In general, it's best to add shock to your hot tub once a week. You can also add it after increased use, such as after a hot tub party. Depending on your needs, you can use chlorine or non-chlorine (oxidizer) shock.

Though both types are fine, non-chlorine shock is better for maintenance. It allows you to get into your tub right after using it. If you notice algae or cloudy water, though, you're better off using chlorine shock.

Line Flush Cleaner

Over time, your hot tub plumbing can start to accumulate dirt, grime, and mineral deposits. This often leads to hot tub scaling, an issue that could damage your fixtures if it's not addressed in time.

The best way to remove buildup from your plumbing is to use a line flush cleaner. Once you've done that, drain your hot tub. Even if you don't see any buildup, you should flush your plumbing 3-4 times a year.

Calcium Hardness Increaser

Do you live in a place that gets hard water? If so, don't despair yet -- some hard water is good for your hot tub! If your water is too soft, it can eat away at your pipes, shell, and other important parts.

The ideal calcium hardness level is between 175 ppm and 250 ppm. If you're not there yet, add a bit of calcium hardness increaser. Don't add too much, as the only solution for high hardness levels is draining and scrubbing the tub.

Optional Chemicals

Depending on the type of your tub, you may want to add some other hot tub cleaning supplies as well. Here are some common examples.

Water Clarifier

As the name implies, a clarifier keeps your water clear. That said, if you're dealing with cloudy water, the clarifier will only treat the symptoms. If you don't address the cause, the water will turn cloudy again soon.

Filter Cleaner

If you're using your hot tub a lot, it's recommended to remove and clean your filters once a week. You can use standard filter cleaning products or phosphate-free detergent granules.

Metal Remover

Water sources that contain iron and copper may leave stains in your tub. The best solution is to use a metal remover. If you're using a mineral sanitizer, use the remover sparingly, as it can make the sanitizer less effective.


Hot tub enzymes help break down leaves, skin cells, and other organic contaminants. If you clean your hot tub regularly and keep the sanitizer level balanced, the enzymes aren't necessary.

What Chemicals Are Needed for a Hot Tub?

There's a lot that goes into keeping a hot tub in good shape. The good news: this hot tub chemical guide has all the advice you need! Instead of googling "what chemicals are needed for a hot tub," bookmark this page now!

Need some of the chemicals we outlined in this guide? At Pool Store Canada, we offer a wide range of high-quality supplies, fast shipping, and secure checkouts! Check out our selection of hot tub chemicals!

Next article What is the cost to maintain your hot tub?

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